yep, you should definitely provide those writing for you some info. at many schools (mine included) the professors of many typical pre-med classes (e.g. organic chem) are used to having people that they have never spoken to ask them to write recommendations. i gave all professors writing for me a transcript, statement of career goals, and resume including extracurricular activities and work experience. you would be surprised at how some react to that info- one professor said that he liked the fact that i worked in a machining shop because it showed that i had character! hmmm...well anyway, the pre-med department at my school recommends at least one letter from a bio prof, 1 from a chem prof, possibly one from a lab director or research prof and 1 personal (like from a rector or previous employer). any from someone in a medical field is valuable, obviously. good luck!